Whittington and his companion were walking at a good pace. Tommystarted in pursuit at once, and was in time to see them turn thecorner of the street. His vigorous strides soon enabled him togain upon them, and by the time he, in his turn, reached thecorner the distance between them was sensibly lessened. The smallMayfair streets were comparatively deserted, and he judged itwise to content himself with keeping them in sight.The sport was a new one to him. Though familiar with thetechnicalities from a course of novel reading, he had neverbefore attempted to "follow" anyone, and it appeared to him atonce that, in actual practice, the proceeding was fraught withdifficulties. Supposing, for instance, that they should suddenlyhail a taxi? In books, you simply leapt into another, promisedthe driver a sovereign--or its modern equivalent--and there youwere. In actual fact, Tommy foresaw that it was extremely likelythere would be no second taxi. Therefore he would have to run.What happened in actual fact to a young man who ran incessantlyand persistently through the London streets? In a main road hemight hope to create the illusion that he was merely running fora bus. But in these obscure aristocratic byways he could not butfeel that an officious policeman might stop him to explainmatters.At this juncture in his thoughts a taxi with flag erect turnedthe corner of the street ahead. Tommy held his breath. Wouldthey hail it?He drew a sigh of relief as they allowed it to pass unchallenged.Their course was a zigzag one designed to bring them as quicklyas possible to Oxford Street. When at length they turned intoit, proceeding in an easterly direction, Tommy slightly increasedhis pace. Little by little he gained upon them. On the crowdedpavement there was little chance of his attracting their notice,and he was anxious if possible to catch a word or two of theirconversation. In this he was completely foiled; they spoke lowand the din of the traffic drowned their voices effectually.Just before the Bond Street Tube station they crossed the road,Tommy, unperceived, faithfully at their heels, and entered thebig Lyons'. There they went up to the first floor, and sat at asmall table in the window. It was late, and the place wasthinning out. Tommy took a seat at the table next to them,sitting directly behind Whittington in case of recognition. Onthe other hand, he had a full view of the second man and studiedhim attentively. He was fair, with a weak, unpleasant face, andTommy put him down as being either a Russian or a Pole. He wasprobably about fifty years of age, his shoulders cringed a littleas he talked, and his eyes, small and crafty, shiftedunceasingly.Having already lunched heartily, Tommy contented himself withordering a Welsh rarebit and a cup of coffee. Whittingtonordered a substantial lunch for himself and his companion; then,as the waitress withdrew, he moved his chair a little closer tothe table and began to talk earnestly in a low voice. The otherman joined in. Listen as he would, Tommy could only catch a wordhere and there; but the gist of it seemed to be some directionsor orders which the big man was impressing on his companion, andwith which the latter seemed from time to time to disagree.Whittington addressed the other as Boris.Tommy caught the word "Ireland" several times, also "propaganda,"but of Jane Finn there was no mention. Suddenly, in a lull inthe clatter of the room, he got one phrase entire. Whittingtonwas speaking. "Ah, but you don't know Flossie. She's a marvel.An archbishop would swear she was his own mother. She gets thevoice right every time, and that's really the principal thing."Tommy did not hear Boris's reply, but in response to itWhittington said something that sounded like: "Of course--onlyin an emergency...."Then he lost the thread again. But presently the phrases becamedistinct again whether because the other two had insensiblyraised their voices, or because Tommy's ears were getting moreattuned, he could not tell. But two words certainly had a moststimulating effect upon the listener. They were uttered by Borisand they were: "Mr. Brown."Whittington seemed to remonstrate with him, but he merelylaughed."Why not, my friend? It is a name most respectable--most common.Did he not choose it for that reason? Ah, I should like to meethim--Mr. Brown."There was a steely ring in Whittington's voice as he replied:"Who knows? You may have met him already.""Bah!" retorted the other. "That is children's talk--a fable forthe police. Do you know what I say to myself sometimes? That heis a fable invented by the Inner Ring, a bogy to frighten uswith. It might be so.""And it might not.""I wonder ... or is it indeed true that he is with us and amongstus, unknown to all but a chosen few? If so, he keeps his secretwell. And the idea is a good one, yes. We never know. We lookat each other--one of us is Mr. Brown--which? He commands--butalso he serves. Among us--in the midst of us. And no one knowswhich he is...."With an effort the Russian shook off the vagary of his fancy. Helooked at his watch."Yes," said Whittington. "We might as well go."He called the waitress and asked for his bill. Tommy didlikewise, and a few moments later was following the two men downthe stairs.Outside, Whittington hailed a taxi, and directed the driver to goto Waterloo.Taxis were plentiful here, and before Whittington's had drivenoff another was drawing up to the curb in obedience to Tommy'speremptory hand."Follow that other taxi," directed the young man. "Don't loseit."The elderly chauffeur showed no interest. He merely grunted andjerked down his flag. The drive was uneventful. Tommy's taxicame to rest at the departure platform just after Whittington's.Tommy was behind him at the booking-office. He took a first-classsingle ticket to Bournemouth, Tommy did the same. As he emerged,Boris remarked, glancing up at the clock: "You are early. Youhave nearly half an hour."Boris's words had aroused a new train of thought in Tommy's mind.Clearly Whittington was making the journey alone, while the otherremained in London. Therefore he was left with a choice as towhich he would follow. Obviously, he could not follow both ofthem unless----Like Boris, he glanced up at the clock, and thento the announcement board of the trains. The Bournemouth trainleft at 3.30. It was now ten past. Whittington and Boris werewalking up and down by the bookstall. He gave one doubtful lookat them, then hurried into an adjacent telephone box. He darednot waste time in trying to get hold of Tuppence. In allprobability she was still in the neighbourhood of South AudleyMansions. But there remained another ally. He rang up the Ritzand asked for Julius Hersheimmer. There was a click and a buzz.Oh, if only the young American was in his room! There was anotherclick, and then "Hello" in unmistakable accents came over thewire."That you, Hersheimmer? Beresford speaking. I'm at Waterloo.I've followed Whittington and another man here. No time toexplain. Whittington's off to Bournemouth by the 3.30. Can youget there by then?"The reply was reassuring."Sure. I'll hustle."The telephone rang off. Tommy put back the receiver with a sighof relief. His opinion of Julius's power of hustling was high.He felt instinctively that the American would arrive in time.Whittington and Boris were still where he had left them. If Borisremained to see his friend off, all was well. Then Tommy fingeredhis pocket thoughtfully. In spite of the carte blanche assuredto him, he had not yet acquired the habit of going about with anyconsiderable sum of money on him. The taking of the first-classticket to Bournemouth had left him with only a few shillings inhis pocket. It was to be hoped that Julius would arrive betterprovided.In the meantime, the minutes were creeping by: 3.15, 3.20, 3.25,3.27. Supposing Julius did not get there in time. 3.29.... Doorswere banging. Tommy felt cold waves of despair pass over him.Then a hand fell on his shoulder."Here I am, son. Your British traffic beats description! Put mewise to the crooks right away.""That's Whittington--there, getting in now, that big dark man.The other is the foreign chap he's talking to.""I'm on to them. Which of the two is my bird?"Tommy had thought out this question."Got any money with you?"Julius shook his head, and Tommy's face fell."I guess I haven't more than three or four hundred dollars withme at the moment," explained the American.Tommy gave a faint whoop of relief."Oh, Lord, you millionaires! You don't talk the same language!Climb aboard the lugger. Here's your ticket. Whittington's yourman.""Me for Whittington!" said Julius darkly. The train was juststarting as he swung himself aboard. "So long, Tommy." Thetrain slid out of the station.Tommy drew a deep breath. The man Boris was coming along theplatform towards him. Tommy allowed him to pass and then took upthe chase once more.From Waterloo Boris took the tube as far as Piccadilly Circus.Then he walked up Shaftesbury Avenue, finally turning off intothe maze of mean streets round Soho. Tommy followed him at ajudicious distance.They reached at length a small dilapidated square. The housesthere had a sinister air in the midst of their dirt and decay.Boris looked round, and Tommy drew back into the shelter of afriendly porch. The place was almost deserted. It was acul-de-sac, and consequently no traffic passed that way. Thestealthy way the other had looked round stimulated Tommy'simagination. From the shelter of the doorway he watched him goup the steps of a particularly evil-looking house and rapsharply, with a peculiar rhythm, on the door. It was openedpromptly, he said a word or two to the doorkeeper, then passedinside. The door was shut to again.It was at this juncture that Tommy lost his head. What he oughtto have done, what any sane man would have done, was to remainpatiently where he was and wait for his man to come out again.What he did do was entirely foreign to the sober common sensewhich was, as a rule, his leading characteristic. Something, ashe expressed it, seemed to snap in his brain. Without a moment'spause for reflection he, too, went up the steps, and reproducedas far as he was able the peculiar knock.The door swung open with the same promptness as before. Avillainous-faced man with close-cropped hair stood in thedoorway."Well?" he grunted.It was at that moment that the full realization of his follybegan to come home to Tommy. But he dared not hesitate. Heseized at the first words that came into his mind."Mr. Brown?" he said.To his surprise the man stood aside."Upstairs," he said, jerking his thumb over his shoulder, "seconddoor on your left."